Spending outcomes among patients with cancer in accountable care organizations 4 years after implementation

Background The long-term impact of affordable care organizations (ACOs) on cancer spending remains unknown. The authors examined whether practices that became ACOs altered their spending for patients with cancer in the first 4 years after ACO implementation. Methods By using national Medicare data from 2011 to 2017, a random sample of 20% of fee-for-service Medicare beneficiaries aged 65 years and older with cancer was obtained (n = 866,532), and each patient was assigned to a practice. Practices that became ACOs in the Medicare Shared Savings Program were matched to non-ACO practices. Total, cancer-specific, and service category-specific yearly spending per patient was calculated. A difference-in-differences model was used to determine spending changes associated with ACO status for patients with cancer in the 4 years after ACO implementation. Results The introduction of ACOs did not have a significant impact on overall spending for patients with cancer in the 2 years after ACO implementation (difference, -$38; 95% CI, -$268, $191; P = .74). Changes in spending also did not differ between ACO and non-ACO patients within service categories or among the 11 cancer types examined. The lack of difference in spending for patients with cancer in ACO and non-ACO practices persisted in the third and fourth years after ACO implementation (difference, -$120; 95% CI, -$284, $525; P = .56). Conclusions ACOs did not significantly change spending for patients with cancer in the first 4 years after their implementation compared with non-ACOs. This prompts a reevaluation of the current efficacy of ACOs in reducing spending for cancer care and may encourage policymakers to reconsider the incentive structures of ACOs. Lay Summary Accountable care organizations (ACOs) were developed to curtail health care spending and improve quality, but their effects on cancer spending in their first 2 years have been minimal. The long-term impact of ACOs on cancer spending remains unknown. By using data from 866,532 Medicare beneficiaries with cancer, the authors observed that the association of a practice with an ACO did not significantly change total yearly spending per patient in the first 4 years after ACO implementation. This finding prompts a reevaluation of the current efficacy of ACOs in reducing spending for cancer care.